Hydraulic press brake and hydraulic system therefor



April 24, 1962 s. E. KEAGLE 3,030,880 g HYDRAULIC PREss BRAKE ANDHYDRAULIC SYSTEM THEREFOR I Filed Nov. 10, 1960 3 Sheets-Sheet 1INVENTOR. STANLEY E. K54

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April 24, 1962 s. KEAGLE 3,030,880

HYDRAULIC PRESS BRAKE AND HYDRAULIC SYSTEM THEREFOR Filed Nov. 10, 19603 Sheets-Sheet 2 FIG. 5

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United States Patent 3,030,880 HYDRAULIC PRESS BRAKE AND HYDRAULICSYEiTEM THEREFOR Stanley E. Keagle, 2626 Nassau St, Sarasota, Fla. FiledNov. 10, 1960, Ser. No. 68,471 14 Claims. (Cl. 100-269) This inventionhas relation to hydraulic press brakes and more particularly to the typeof press brake that travels a portion of the work stroke unloaded orunder relatively light loads and then must exert a relatively greaterforce to accomplish a desired operation.

Present hydraulic presses use a single stage cylinder for power. Inorder to have enough force for heavy jobs at a safe working pressure thepiston of the power cylinder must be relatively large. The filling ofthe cylinder then tages a considerable amount of time. This slows theproduction of the press and limits its output and usefu1- ness.

A hydraulic press made according to the present invention incorporates ahydraulic power cylinder of relatively small size that will rapidlyadvance a press platen to the Work and when the force on the workexceeds a predetermined value an auxiliary hydraulic system becomesoperative to make the force upon the work a multiplication of the forceexerted by the hydraulic power cylinder.

In the form of the invention as shown, this force multiplication isobtained through utilization of a two-section platen that is resilientlyheld together when the platen is under no load. As disclosed, the pistonrod for the main power cylinder is slidably fitted through the upperplaten section and engages a cylindrical opening that has been boredinto the lower section. The piston rod end surface acts as a separatepiston when it moves within the cylindrical opening in the secondsection. This cylindrical opening is connected in parallel with aplurality of auxiliary cylinders bored into the lower section of theplaten. The upper section of the platen has an equal number of auxiliarypistons fixedly attached thereto and extending into the respectivecylinders in the lower section. The cylinder in the second section forthe power cylinder piston rod and the connecting passages to theauxiliary cylinders contain hydraulic fluid and form a closed hydraulicsystem. When a predetermined force or pressure has been reached in thisclosed system the upper section of the platen is locked with respect tothe press frame. The power piston rod continues to move within thecylindrical opening in the lower section of the platen, a hydraulicpressure continues to be built up within said cylindrical opening and anequal pressure will result in each of the auxiliary cylinders. Thiscauses the lower section of the platen to move with respect to the uppersection against the action of the resilient means that urges thesections together. The total force exerted by the lower section will beproportional to the number of auxiliary cylinders and their respectivecross sectional area in relation to the cross sectional area of thepower piston rod acting in its cylindrical opening in the lower section.The force exerted by the lower section of the platen is applied directlyto the work. When the power cylinder is retracted the upper section ofthe platen is released and the two sections are again resiliently urgedtogether and will move as a unit.

Utilization of auxiliary cylinders and pistons in the two-section platenwill allow any desired multiplication of force on the work. The movementof the lower section of the platen with respect to the upper sectionwill be proportionally less than the movement of the power piston rodand this will be dependent on the number of the auxiliary cylinders inthe lower section and their respective sizes.

It is an object of the present invention to present a device that willautomatically provide a multiplication of force exerted by a hydraulicpress after the work has been contacted.

In the drawings:

FIG. 1 is a front elevational view of a hydraulic press made accordingto the present invention with parts broken away to show a hydraulic pumpand control valve;

FIG. 2 is a top plan View of the device of FIG. 1;

FIG. 3 is a view taken as on line 3-3 in FIG. 2 with parts in sectionand parts broken away;

FIG. 4 is a sectional view taken as on line 44 in FIG. 2; and

FIG. 5 is a sectional view taken as on line 55 in FIG. 4.

Referring to the drawings and the numerals of reference thereon, ahydraulic press 19 includes a frame 11 that has two outer longitudinalmembers 12, 12 and two inner longitudinal members 18, 18. Each outermember and its respective adjacent inner member are fixedly joinedtogether adjacent first ends thereof with end members 13, 13. A cylindersupport 14 fixedly joins the two inner members adjacent said first ends.An anvil 15 is fixedly positioned against integral upright portions 16of the longitudinal members at a second end of said longi-' tudinalmembers.

A hydraulic power cylinder 17 is fixedly positioned against cylindersupport 14 and extends toward anvil 15 between inner members 18, 18. Apiston rod 26 is attached to an internal power piston 28 and extends toengage a platen 21 that is slidable on the longitudinal frame membersand extends therebetween. Platen 21 consists of a first section 22 and asecond section 23 that are re-' siliently urged together by a pluralityof springs 24 acting on bolts 25 that in turn are slidable in firstsection 22 and fixedly attached to said second section 23.

First section 22 of the platen has two fixedly attached guide shafts 26,26 that extend substantially parallel to the longitudinal frame membersand are slidably mounted through guide blocks 27, 27 each of which issupported by the longitudinal frame members and is fixedly retainedthereto by notches 29, 29. Guide blocks 27, 27 are braced back to endmembers 13, 13 with struts 30, 30.

A first brake block 31, and a second brake block 32 are pivotallyattached to each of guide blocks 27 with a pin 38 and are positioned toengage each of the guide shafts 26. Each of the second brake blocks 32has a cylinder 33 bored into it and a pressure tight piston 34 fittedwithin said cylinder. A rod 35 is fixedly attached to the brake pistonand extends slidably through first brake block 31. A nut 36 isthreadably fitted onto rod 35 and engages first brake block 31 and movesthe blocks toward each other where the piston is acted upon by hydraulicpressure. An oil passage 37 is located in each of second brake blocks 32and opens into cylinder 33 between piston 34 and the interior end of thecylinder.

Piston rod 20 is slidably fitted through first section 22 of the platen21 and extends to slidably engage a master cylinder 40 in the secondplaten section 23. A lower surface 19 of rod 20 acts as a master pistonwithin said master cylinder. A plurality of slave pistons 41 are fixedlyattached to the first platen section 22 and each extends to slidablyengage an aligning slave cylinder 42 located in second section 23. Apressure tight element 43 seals each of the slave cylinders 42 andmaster cylinder 40 with respect to their respective pistons. A port 44connects all of the slave cylinders 42 and master cylinder 46 inparallel and provides passageway for hydraulic oil to flow between saidcylinders. A pair of pressure lines 45, 45 are connected to port 44- andone of said lines is connected to passageway 37 in each of the secondbrake blocks 32, 32. With the two sections of the platen contiguous, thepistons 41 extend substantially to the bottom of their respectivecylinders and the piston rod 20 is posi- 3 tioned with the end surface19 thereof adjacent the outer end of master cylinder 40. Port 44, thepressure lines 45, 45 master cylinder 40, slave cylinders 42 and brakecylinders 33, 33 in each of the brake blocks 32 are filled withhydraulic oil. This system becomes an independent closed circuithydraulic system.

A cross arm 46 is fixedly attached to piston rod 20 and has two bolts4-7, 47 slidably mounted therein. Bolts 47, 47 are fixedly attached tofirst section 22 of the platen. When the piston rod is retracted, crossarm 46 engages the head portions 50 of the bolts and thereby moves theplaten to a retracted position.

The frame 11 and associated parts are supported by a cabinet 51 or othersuitable structure. Hydraulic fluid under pressure is supplied to thepower cylinder 17 by a hydraulic pump 52 that is driven by an electricmotor 53. A control valve 54- is employed to divert flow from the pumpselectively through a first oil line 55 or a second oil line 56, each ofwhich are open to the interior cylinder 17 on opposite sides of theinternal piston. A relief valve 57 is connected in one of the oil linesto prevent excessive pressure buildup in the line.

Any tendency of the second section of the platen to cock or bind withrespect to the first section is counteracted by pinion gears 58, 58drivably mounted on a transverse torsion shaft 59 that is rotatablymounted on brackets 60, 6t; which in turn are fixedly attached to thesecond section 23 of the platen with bolts 61, 61. A rack 62 is fixedlyattached to each of the outer longitudinal members 12 and each rackextends inwardly therefrom to drivably engage one of pinion gears 58.Thus, if one of the ends of the second section of the platen tends tocock when loaded, the unequal movement of the ends is restrained by therack and pinion acting through the torsion shaft 59 and brackets 60. Thepinion gears will not twist with respect to each other but must rotatetogether. When the second section of the platen tends to cock one of thebrackets 60 will tend to move more than the other. This in turn tends torotate one of the pinion gears 58 more than the other. The rotationalmovement of the pinion gear is transmitted by shaft 59 to the otherpinion gear, thereby equalizing the movement of both ends of the secondsection of the platen or alternatively equalizing the load exerted atthe ends of the second section if additional movement is not possible. Aslot 63 is provided in each of the inner longitudinal members 18 for thetorsion shaft 59 so that it may move longitudinally.

Operation When the press is to be used, as for example to make permanenta fold in the signatures of a book 64, the motor 53 is started and thehydraulic pumpv 52 is thereby activated. The book 64 may be placed onthe anvil 15 and the power cylinder 17 activated by moving the hydrauliccontrol lever to position to divert flow through line 55 to the interiorof said cylinder. The first and second sections of the platen will becontiguous to form a single unit under the action of springs 24 actingthrough bolts 25. The brake blocks 31 and 32 will be released from bothguide shafts 26, 26 and the guide shafts may move freely in guide blocks27, 27. The power piston 28 and the piston rod 20 will be extended bythe hydraulic pressure in cylinder 17 and will move the platen towardthe anvil by the pressure on the end surface 19 of the piston rod 20bearing on the column of hydraulic oil in master cylinder 40. The spring24 holding the two platen sections together will be adjusted tocounteract the pressure necessary to move the platen under no load,thereby insuring that the section will move as a unit. When the platencontacts the work piece, the pressure within master cylinder 40 willrise and the resulting pressure in cylinder 33 in each of the secondbrake blocks 32, 32 will cause the first and second brake blocks to movetogether and lock each of the guide shafts from further slidingmovement. As the piston rod continues to slide within master cylinder4t) the hydraulic oil within the cylinder will be forced through port 44to the slave cylinders 42 and the pressure in the slave cylinders 42will be equal to the pressure in master cylinder at This pressure actingon the slave pistons 41 will force the second section of the platen tomove against the work and away from the first section of the platen.This action is best illustrated in FIG. 2. The total force exerted onthe work is determined by the number of slave cylinders and the area ofsaid slave cylinders in re lation to the area of end surface 19 ofpiston rod 20 and master cylinder 40. As illustrated, with four slavecylinders each with a cross sectional area equal to the cross sectionalarea of master cylinder the total force exerted on the work by thesecond section of the platen will be four times the force exerted bypiston rod 20, minus the force necessary to overcome the force fromsprings 24. Conversely, the movement of the second section of the platenwith respect to the first section thereof will be one-fourth of themovement of piston rod 20 within master cylinder 40.

When oil is diverted from the pump through line 56 to power cylinder 17the power piston rod is retracted,

' the pressure in master cylinder 40 is thereby relieved and the brakeblocks holding the guide shafts 26, 26 will be released. The springs 24will resiliently urge the two sections of the platen into contactingrelationship. As piston rod 20 retracts, cross arm 46 will contact boltheads and the bolts 47 will in turn move the platen away from the workas the piston rod continues to be retracted The power cylinder 17 may beof a size to permit rapid filling until the work is contacted, therebymaking the unloaded stroke of the platen fast. When the work iscontacted the lower section of the platen will automatically move inrelation to the first section with a force multiplication therebyinsuring sufficient power to accomplish most press brake jobs. Thestroke will then also be proportionately slower to make control of theplaten easier. The return stroke also will be rapid because of therelatively small size of cylinder 17.

While the device as disclosed is shown operating in a horizontalposition a vertical press brake may utilize the same type of platen.Also a V-die or other metal forming equipment may be inserted into thepress brake and equally excellent results will be obtained. The rapidreturn and unloaded strokes of the piston rod greatly increase theeificiency and total output of the press brake. The total force that maybe exerted by the brake will still be large enough to accomplish mostheavy jobs.

What is claimed is:

1. A hydraulic press brake including a main frame, a work anvil mountedwith respect to said frame, a hydraulic power cylinder mounted withrespect to said frame, a power piston slidably mounted in said powercylinder, a source of fluid under pressure, a conduit open to saidsource of fluid under pressure and to the interior of said powercylinder, control means in said conduit for selectively diverting saidfluid under pressure to said power cylinder, a first platen sectionslidably mounted with respect to said frame, a second platen sectionslidably mounted with respect to said first platen section, bias meansurging said platen sections together, a piston rod link operablyassociated with said power piston, a master hydraulic unit comprising'two master hydraulic components, namely a master cylinder and a masterpiston operably associated with said master cylinder, with one of saidmaster hydraulic components being operably associated with said secondplaten section and the other of said master hydraulic components beingoperably associated with said piston rod link, at least one slavehydraulic unit comprising two slave hydraulic components, namely a slavecylinder and a slave piston operably associated with said slavecylinder, with one of said slave hydraulic components operablyassociated with said first platen section and the other slave hydrauliccomponent operably associated with said second platen section, therebeing a passageway open to the interior of said master hydraulic unitand the interior of said slave hydraulic unit, the interior of saidmaster hydraulic unit, the interior of said slave hydraulic unit andsaid passageway constituting a closed hydraulic system, and means forimmobilizing with respect to said frame the platen section locatedfarthest away from said anvil responsive to increase of pressure in saidclosed hydraulic system.

2. A hydraulic press brake including a main frame, a work anvil mountedwith respect to said frame, a hydraulic power cylinder mounted withrespect to said frame, a power piston slidably mounted in said powercylinder, a piston rod link operably associated with said power piston,a source of fluid under pressure, a conduit open to said source of fluidunder pressure and to the interior of said power cylinder, control meansin said conduit for selectively diverting said fluid under pressure tosaid power cylinder, a first platen section slidably mounted withrespect to said frame, a second platen section slidably mounted wtihrespect to said first platen section, bias means urging said platensections together, a master hydraulic unit comprising two masterhydraulic components namely a master cylinder and a master pistonoperably associated with said master cylinder, one of said masterhydraulic components being fixedly attached with respect to said one ofsaid platen sections and the other master hydraulic component beingoperably associated with said piston rod link, at least one slavecylinder mounted With respect to said second platen section, a slavepiston operably engaging said first platen section and operablyassociated with said slave cylinder, there being a passageway open tothe interior of said master hydraulic unit and the interior of saidslave cylinder, the interior of said master hydraulic unit, the interiorof said slave cylinder and said passageway constituting a closedhydraulic system, and means for immobilizing with respect to said framethe platen section located farthest away from said anvil responsive toincrease of pressure in said closed hydraulic system.

3. A hydraulic press brake including a main frame, a work anvil mountedwith respect to said frame, a hydraulic power cylinder mounted withrespect to said frame, a power piston slidably mounted in said cylinder,a piston rod fixedly attached to said power piston, a source of fluidunder pressure, a conduit open to said pressure source and to theinterior of said power cylinder, control means in said conduit forselectively diverting said fluid under pressure to said power cylinder,a first platen section slidably mounted with respect to said frame, asecond platen section slidably mounted with respect to said first platensection, bias means urging said platen sections together, a mastercylinder fixedly mounted with respect to one of said platen sections, amaster piston operably associated with said master cylinder, meansoperably connecting said power piston rod and said master piston, atleast one slave cylinder fixedly attached with respect to said secondplaten section, a slave piston operably engaging said first platensection and operably associated with said slave cylinder, there being apassageway open to the interior of said master cylinder and the interiorof said slave cylinder, the interior of said master cylinder, saidpassageway and the interior of said slave cylinder constituting a closedhydraulic system, and means for immobilizing with respect to said framethe platen section located farthest away from said anvil responsive toincrease of pressure in said closed hydraulic system.

4. The combination as specified in claim 3 wherein said means forimmobilizing said platen section includes brake means fixedly attachedwith respect to said frame and associated With said platen section, saidbrake means being operable to hold said section immobile responsive toincrease of pressure in said closed hydraulic system.

5. The combination as specified in claim 4 wherein said master cylinderis fixedly mounted with respect to said second platen section andwherein said brake means is associated with said first platen section.

6. The combination as specified in claim 5 and means to prevent a firstend of said second platen section from traveling a different distancewith respect to said first platen section than a second end of saidsecond platen section.

7. A hydraulic press brake including a main frame, a work anvil mountedwith respect to said frame, a hydraulic power cylinder mounted withrespect to said frame, a power piston slidably mounted in said cylinder,a power piston rod fixedly attached to said power piston, a source offluid under pressure, a conduit open to said pressure source and to theinterior of said power cylinder, control means in said conduit forselectively diverting said fluid under pressure to the interior of saidpower cylinder and thereby moving said piston and attached rod towardsaid anvil, a first platen section slidably mounted with respect to saidframe, a second platen section slidably mounted with respect to saidfirst platen section, bias means resiliently urging said platen sectionstogether, a master cylinder located in said second section, a masterpiston operably engaging said master cylinder, said power piston rodbeing slidably mounted with respect to said first platen section andoperably associated with said master piston, a plurality of slavecylinders fixedly attached with respect to one of said platen sections,a plurality of slave pistons fixedly attached with respect to the platensection not associated with said slave cylinders, each of said slavepistons being operably associated with one of said slave cylinders,therebeing a passageway open to the interior of said master cylinder andthe interior of each of said slave cylinders, brake means fixedlyattached with respect to said frame and operably associated with saidfirst platen section, a brake cylinder operably associated with saidbrake means, and a passageway open to the interior of said mastercylinder and the interior of said brake cylinder, the interior of saidmaster cylinder,

said passageways, the interior of each of said slave cylin ders and theinterior of said brake cylinder constituting a closed hydraulic system,with said brake cylinder positioned to actuate said brake means to holdsaid first platen section immobile when the pressure within said closedhydraulic system exceeds a predetermined level.

8. The combination as specified in claim 7 and means to prevent a firstend of said second platen section from traveling a different distancethan a second end of said second platen section with respect to saidfirst platen section.

9. The combination as specified in claim 8 wherein said means to preventsaid ends of said second platen section from traveling differentdistances with respect to said first platen section includes a shaftrotatably mounted with respect to said second platen section, a piniongear drivingly mounted adjacent each end of said shaft, and a rackfixedly attached with respect to said frame adjacent each end of saidshaft and drivingly engaging one of said pinion gears.

10. A hydraulic press brake including a main frame, a Work anvil mountedwith respect to said frame, a hydraulic power cylinder mounted withrespect to said frame, a power piston slidably mounted in said cylinder,a power piston rod fixedly attached to said power piston, a source offluid under pressure, a conduit open to said pressure source and to theinterior of said power cylinder, control means in said conduit forselectively diverting said fluid under pressure to said cylinder andthereby moving said piston and attached rod toward said anvil, a firstplaten section slidably mounted with respect to said frame, at least oneguide block fixedly attached with respect to said frame, at least oneguide rod fixedly attached to said spanner;

first platen section and slidably mounted through said guide block, asecond platen section siidably mounted with respect to said first platensection, bias means res'liently urging said second platen section intocontacting relationship with said first platen section, a mastercylinder located in said second platen section, said power piston rodbeing slidably mounted through said first platen section with the lowerportion of said power piston rod constituted as a master piston operablyengaging said master cylinder, a plurality of slave cylinders located insaid second platen section, a plurality of slave pistons fixedlyattached with respect to said first platen section and each operablyassociated with one of said slave cylinders, brake means mounted on saidguide block and operably engaging said guide rod, a brake actuatingcylinder operably associated with said brake means, and therebeing apassageway connecting the interior of said master cylinder, the interiorof each of said slave cylinders, and the interior of said brake cylinderin parallel, said passageway and said parallel connected cylindersthereby forming a closed hydraulic circuit, with said brake meanengaging said guide rods and holding said first section of said platenimmobile when the pressure within said closed hydraulic system exceeds apredetermined level.

11. The combination as specified in claim 10 wherein said bias meansincludes a plurality of coil s rings positioned to urge the platensections together.

12. The combination as specified in claim 10 wherein said brake meansincludes a pair of brake blocks pivotally attached with respect to saidguide block and with respect to each other and substantially encirclingsaid guide rod, said brake cylinder being fixedly attached with respectto a first of said brake blocks and having an internal piston withattached piston rod positioned to operably engage a second of said brakeblocks and to move said blocks together to lock said guide rod when thepressure within said closed hydraulic system exceeds a predeterminedlevel.

13. A hydraulic press brake including a main frame, a work anvil mountedwith respect to said frame, a power hydraulic unit comprising two powerhydraulic components, namely a power hydraulic cylinder and a powerpiston slidably mounted in said power cylinder, a first of said powerhydraulic components being mounted with respect to said frame, a pistonrod link operable associated with a second of said hydraulic components,a source of fluid under pressure, a conduit open to said source of fluidunder pressure and to the interior of said power cylinder, control meansin said conduit for selectively diverting said fluid under pressure tosaid power cylinder, a first platen section slidably mounted withrespect to said frame, a second platen section slidably mounted withrespect to said first platen section, bias means urging said platensections together, a master hydraulic unit comprising two masterhydraulic components, namely a master cylinder and a master pistonoperably associated with said master cylinder, with one of said masterhydraulic components being operably associated with said second platensection and the other of said master hydraulic components being operablyassociated with said piston rod link, at least one slave hydraulic unitcomprising two slave hydraulic components, namely a slave cylinder and aslave piston operably associated with said slave cylinder, with one ofsaid slave hydraulic components operably associated with said firstplaten section and the other slave hydraulic component operablyassociated with said second platen section, therebeing a passageway opento the interior of said master hydraulic unit and the interior of saidslave hydraulic unit, the interior of said master hydraulic unit, theinterior of said slave hydraulic unit and said passageway constituting aclosed hydraulic system, and means for immobilizing with respect to saidframe the platen section located farthest away from said anvilresponsive to increase of pressure in said closed hydraulic system.

14. A press brake including a main frame, a work anvil mounted withrespect to said frame, a first platen section slidably mounted withrespect to said frame, a second platen section slidably mounted withrespect to said first platen section, bias means urging said platensections together, power thrust means mounted with respect to saidframe, a piston rod link operably associated with said power thrustmeans, a master hydraulic unit comprising two master hydrauliccomponents, namely a master cylinder and a master piston operablyassociated with said master cylinder, one of said master hydrauliccomponents being operably associated with said second platen section andthe other of said master hydraulic components being associated with saidpiston rod link, at least one slave hydraulic unit comprising two slavehydraulic components, namely a slave cylinder and a slave pistonoperably associated with said cylinder, with one of said slave hydrauliccomponents operably associated with said first platen section and theother slave hydraulic component operably associated with said secondplaten section, t-herebeing a passageway open to the interior of saidmaster hydraulic unit and the interior of said slave hydraulic unit, theinterior of said master hydraulic unit, the interior of said slavehydraulic unit and said passageway constituting a closed hydraulicsystem, and means for immobilizing with respect to said frame the platensection located farthest away from said anvil responsive to increase ofpressure in said closed hydraulic system.

References Cited in the file of this patent UNITED STATES PATENTS2,302,953 Popock Nov. 24, 1942 2,603,176 Sebring et a1. July 15, 19522,855,628 Lassman Oct. 14, 1958

